Black Liquor Gasification Design Project GP Wauna

1. Black Liquor Gasification Design ProjectGP Wauna Gasifier Design Justin Aldrich, Adam Cooper, Khoa Hua, Jim Jollimore Mill Integration Sean Noste, Steve Ross, John Salvatier, Peter Siedenburg, Nilar Thein-chen Environmental Cody Hargrove, Sonha Pham, Claire Schairbaum, Larissa Zuk Economics Darrow Conley, Ryan McMahon, Vinh Nguyen, Suzy Quach

2. Agenda Gasifier Design Mill Integration Environmental Economics

3. High Temperature Gasification Image Source: http://www.eng.utah.edu/~whitty/blackliquor/colloquium2003/pdfs_handouts/5.6.Lindblom-Chemrec_Handout.pdf

4. High Temperature Gasification Gasifier values from Larson 2003. Natural gas value from Wikipedia. H2S in Syngas values from Larson 2003. • Syngas Properties: • Heating Value • Sulfur

5. High Temperature Gasification • Effect on Causticization Load • Reliability • Weyerhauser, New Bern, Chemrec Booster 1996.

6. Low Temperature: Pros • Low Temperature • Better return on energy • Ease of getting chemicals back • H2S is in a gaseous form • Proven system that is currently running • Norampac Trenton Ontario • Use heat to produce needed steam and electricity

7. Low Temperature: Con • Need additional equipment to recover Chemicals • Air scrubbers to recover SO2 • Higher initial cost than High Temp • ~32% higher initial startup cost

8. BL Solids @ 67% Solids Cooling Water Vent 95% O2, 20°C Raw Syngas, 122°C High Temp Gasifier 1000°C 35 bar 165 TPD O2 Plant To Lime Kiln 2 Stage Gas Cooler or Heat Exchanger LP Steam? Raw Syngas 200°C 35 bar Cooling Water? Air, 20°C Cooled Green Liquor 132°C GL Cond HX Clean Syngas 40°C ~30 Bar H2S and CO2 WL Scrubber Selexol Absorber 40 °C ~30 bar Selexol Stripper 40 °C ~30 bar High Sulfidity White Liquor White Liquor Trim Cooler Raw Syngas, 40°C LP Steam

9. Raw Syngas, 600°C Steam Cooling Water Clean Syngas Low Temp Gasifier 650°C 1.2 bar 165 TPD PC Heater Flue Gas HX Low Pressure Superheater Heat Exchanger BL Solids @ 67% Solids Superheated Steam LP Steam or Warm Water Mix Tank & Filter Dregs Clean Syngas 40°C Compressor Na2CO3 H2S and CO2 WL Scrubber Selexol Absorber 40 °C ~25 bar Selexol Stripper 40 °C ~25 bar High Sulfidity White Liquor Or Green Liquor White Liquor Trim Cooler Raw Syngas, 40°C LP Steam

10. Claus Plant 2H2S + O2 → S2 +2H2O Converts H2S gas into elemental sulfur Has two parts: thermal stage and catalytic stages Operates at moderate temperatures (340° C to 200° C) Uses Titanium Dioxide or Alumina as a catalyst 94 to 97% efficiency depending on the number of catalytic stages

11. Liquor Scrubbing H2S + 2NaOH → Na2S + 2H2O • Product gas stream contains CO2 and H2S • Scrubbing CO2 generates Na2CO3 which increase the lime kiln load • Use the NaOH in the liquor to regain the pulping chemical Na2S • 85% efficiency at sulfur recovery

12. CrystaSulf 2H2S + SO2 → ⅜ S8 + 2H2O + 33kcal/gmole • Uses SO2 to convert H2S into elemental sulfur • Operates at lower temperatures (170 °C) • Claims to be more economical for 0.2 to 30 LTPD H2S flows • Uses hydrocarbons and amines as catalysts

13. Mill Integration: Objective • Energy and Mass Balance on Process • Create WinGEMS Model • Determine Impact of Gasifier • Effect of Burning Syngas in Lime Kiln • Transportation of Syngas

14. Schematic from Wauna Mill

15. Steam Balance Calculation

16. Calculation Comparison

17. Kraft Pulp Mill and Recovery CaO Steam Make-Up vents Fresh shower water Greenliquor Whiteliquor Wood chips 1800 gal total/min Chip White liquor clarifier Clarified green liquor clarifier presteam Black 581.3 gal total/min 724 gal total/min Clarified white liquor 2116 od st/day liquor TTA: 130 g/l as NaOH Brownstock Slaker Unbleached pulp washers To 1003 od st/day 16.1 mt/hr Makeup scrubber 1302 gal total/min 4.2 gal total/min CONTINUOUSDIGESTER 31 psig NaOH 0.0002 g/l as NaOH EA 34 cons% 1653 gal total/min Flash Flash 10 cons% Grits tank tank Makeup chemicals to mix tank Wash Dregs Filtrate zone Weak Flue gas black Spills Scrubber 177.2 gal total/min Weak wash Weak wash to SDT liquor 36 cons% 1577.1 gal total/min 687 gal total/min White liquor 16.5 %mass to digesters Recovery Shower Pulp yield: EA: 107 g/l as NaOH Evaporators water 47.4 % Boiler Sulfidity: 28 % Digester 581 gal total/min Strong black liquor Flue Lost flash steam Air gas lime dust 302.2 gal total/min 64 %mass Spent acid LimeKiln Mud Fresh water washer makeup Recovered Fuel 542 gal total/min sulfur Stream59flowismanipulated to achieve a TTA of 130 g/l as NaOH Makeup chemicals in the green liquor, stream 50. Lime SDT Smelt Air Mud washer and filter filtrates BL spills Tall Condensate oil WinGEMS Full Mill Created By Pacific Simulation

18. Kraft Pulp Mill and Recovery White liquor 0 gal total/min Wood chips 420 od st/day Unbleached pulp 0 od st/day 0 gal total/min 0 g/l as NaOH EA CaO Steam Make-Up vents Fresh shower water Greenliquor Whiteliquor Wood chips 1800 gal total/min Chip clarifier Clarified green liquor clarifier presteam Black 0 gal total/min Clarified white liquor liquor 1000 od st/day TTA: 0 g/l as NaOH Brownstock Slaker washers CONTINUOUSDIGESTER To 0 mt/hr Makeup scrubber 0 gal total/min -14.7 psig NaOH 0 cons% 0 gal total/min 0 cons% Flash Flash Grits tank tank Makeup chemicals to mix tank Wash Dregs Filtrate zone Weak Flue gas black Spills Scrubber 0 gal total/min liquor Weak wash Weak wash to SDT 0 cons% 0 gal total/min 1300 gal total/min White liquor 0 %mass to digesters Shower Pulp yield: EA: 0 g/l as NaOH water 0 % Sulfidity: 0 % Digester 0 gal total/min Flue Lost flash steam Air gas lime dust LimeKiln Mud Fresh water washer makeup Fuel 626 gal total/min Stream 59 flow is manipulated to Recovery achieve a TTA of 130 g/l as NaOH Evaporators Strong black liquor Lime Boiler in the green liquor, stream 50. 0 gal total/min 0 %mass Mud washer and filter filtrates Spent acid Recovered sulfur Makeup chemicals SDT Smelt Air BL spills Tall Condensate oil WinGEMS Modification

19. Burning Syngas in Lime Kiln • Combustion in kiln and TADs • Sulfur needs to be scrubbed from syngas • Send scrubbed sulfur to kiln for recovery • Combustion in kiln only • No need to scrub sulfur from syngas • Potential increase in ball and ring formation from sulfur

20. Transportation of Syngas • Hydrogen is main component in syngas • Amount of carbon in steel decreases when in contact with hydrogen creating pockets • Methane forms in pockets inside the steel causing steel to become brittle • Choice of material is very important

21. Mill Integration: Conclusion • Modified WinGEMs Simulation Adequately • Future comparison of High and Low Temp • Using WinGEMS • Comparing chemical balances • Steam balance • Load on lime kiln • Optimal use of syngas

22. Air Emissions Black liquor gasifier system should have low air emissions including: CO2(Carbon Dioxide) SO2(SulfurDioxide) NOX (Nitride Oxides) VOCs (volatile organic compounds) TRS emissions (Total Reduced Sulfur) A lot of contaminant removal is required to recover the pulping chemicals from the gas

23. Air Emissions: High Temp vs. Low Temp Figure 1. Emissions estimated for low temperature and high temperature gasifiers. The values were calculated using a 353 day operating schedule per year. Source: Larson, E.D., & Consonni, S., & Katofsky, R.E. (2003). A Cost-Benefit Assessment of Biomass Gasification Power Generation in the Pulp and Paper Industry.

24. Air Emissions: Mill Limits Figure 2. These are emission standards for the Georgia-Pacific mill in Wauna. Source: Oregon Department of Environmental Quality. (2005). Oregon Title V Operating Permit (Permit Number 04-0004). Portland, OR.

25. Water Emissions & Usage • Two water issues associated with the addition of gasifier: • Water Usage • Thermal Pollution • Secondary treatment facility has a maximum capacity of 42 million gal/day. • In 2007, GP Wauna averaged 27.3 million gal/day. • There is no way the gasifier will cause the mill to increase its water consumption by 15 million gal/day.

26. Thermal Pollution Maximum allowable discharge temperature from secondary treatment plant is 20 °C. In 2007, GP Wauna’s secondary treatment was fed waste water at a temperature of 29.3 °C. The addition of 7.2 million gpd at 40 °C from the gasifier could potentially raise the temperature of the discharge waste water stream by 2 °C.

27. Syngas Exposure • Carbon Monoxide – PEL 50 ppm • EXTREMELY toxic • Flammable • Hydrogen – No PEL • Not toxic; excessive exposure may lead to asphyxiation • EXTREMELY flammable • Carbon Dioxide – PEL 5,000 ppm • Toxic

28. Syngas Storage • Store in well ventilated areas. • Store where temperature is less than 50 °C • Remove sparking and ignition hazards • Stainless steel is satisfactory • Risk of embrittlement with hydrogen • Syngas is not pure hydrogen, so embrittlement risk is minimal

29. Natural Gas Usage

30. Raw Syngas Component

31. Raw Syngas Produced

32. CO2 Produced

33. Social Impact • Benefit • Improve the economics • Greenhouse gases reduction • Lower net emission of CO2 • Possible downside • Water thermal discharge

34. Economics: Agenda • Major Equipment • Summary of Calculation • Capital Cost Analysis • Cost Reduction • Conclusions

35. Major Equipment and Components • Gasifier • Air Separation Unit • Sulfur Recovery Unit (SRU) • Selexol/Rectisol • Green Liquor Scrubber • Gas Cooler (Heat Exchangers)

36. Summary of Calculation • Capital cost adapted from Eric Larson’s A Cost-Benefit Assessment of Biomass Gasification Power Generation in the Pulp and Paper Industry • Adjustment made with High Temp • 2002$ inflated to 2008$ • Scaled to Wauna specifications using 6-tenths factor • 2576.8 tons BL/day  165.6 tons BL/day • Lang factor used to estimate indirect costs from direct costs

37. Capital Cost Analysis

38. Cost Reduction Analysis

39. Conclusions • Low Temp Gasification • Higher up front cost • Higher ROI • Better at replacing natural gas with Syngas • High Temp Gasification • Lower up front cost • Lower ROI • Consult with design team • Stability against Natural Gas Increase

40. Questions